1. Field of the Invention
The invention relates to an electrical modular terminal, especially for latching onto a mounting rail, with a base terminal and with a plug, the base terminal having a terminal housing, at least one terminal element located in it and at least two sockets which are electrically connected to the terminal element or terminal elements, the plug having a plug housing, at least one terminal element located therein and a plug-in contact which is electrically connected to the terminal element or the terminal elements, and the plug being mechanically connected by means of a fastener to the terminal housing of the base terminal. Here, the terminal housing and the plug housing are preferably made of insulating material.
2. Description of Related Art
An electrical modular terminal of the initially mentioned type is known from published German Utility Model DE 295 14 711 U1. Here, the base terminal is generally latched onto a mounting rail so that the base terminal represents the stationary part of the electrical modular terminal. Conversely, the plug represents the movable part of the electrical modular terminal since it can be easily slipped onto the corresponding sockets of the base terminal and withdrawn from them again by means of its plug-in contact. While the electrical supply lines are connected to the base terminal or to the terminal elements located in the base terminal, the electrical lines of the individual consumers are connected to the terminal element in the plug. Here, the electrical modular terminals are generally made disk-shaped; they are generally mated to several other electrical modular terminals into a modular terminal block. In these known electrical modular terminals, it is then possible to reduce the wiring work and thus also the installation cost by connecting the electrical conductors of individual consumers to a corresponding number of plugs. Then, the plugs which can be combined into a plug block need only be inserted into a base terminal block, the base terminal block having been composed of a corresponding number of base terminals.
The disadvantage in the electrical modular terminal known from German Utility Model DE 295 14 711 U1 is that the base terminal does indeed have two sockets, but the plug can only be plugged into the outer of the two sockets. This is because the fastener for secure mechanical connection of the plugs and base terminal is attached to the end face of the plug and fits behind a projection of the housing on the end face of the base terminal. The known electrical modular terminal has two terminal elements in the base terminal so that two supply lines can also be connected to the stationary side of the electrical modular terminal. To be able to connect two electrical lines on the other movable side of the modular terminal, the plug also has two terminal elements. However, due to the arrangement of two terminal elements in the plug, the plug is so wide that the second inside socket of the base terminal is covered by the housing of the plug, and thus, is no longer accessible. In this way, another disadvantage arises, i.e., that the possibility of connecting two potentials to the electrical modular terminal which is established on the input side by the arrangement of two terminal elements in the base terminal can no longer be used on the output side since only one socket can be occupied.
In the electrical modular terminal known from DE 295 14 711 U1, the plug can be mechanically locked to the plug housing of the base terminal using an elastic catch arm. To do this, the catch arm has a catch hook on its lower end which can be engaged to a corresponding projection on the plug housing of the base terminal. In order to detach the plug from the base terminal again, the tip of a screwdriver must be used to disengage the catch hook and the projection on the housing. To do this, in the area of the catch hook, there is a pocket on the fastener for inserting the tip of a screwdriver. Thus, the pocket is also located on the lower end of the fastener so that it is only poorly accessible from the operator side. This can be a problem, especially when the electrical modular terminal is located, for example, in a switching cabinet where very little space is available between the modular terminal and the corresponding side wall of the switching cabinet.
A primary object of this invention is, thus, to improve an electrical modular terminal of the initially described type such that the two sockets of the base terminal can be used to plug in a plug, but in both cases there must be a detachable mechanical attachment of the plugs and base terminal.
This object is achieved, essentially first of all, in that an interlock recess is formed in the housing of the base terminal between the two sockets so that the plug on both sockets can be mechanically connected to the terminal housing of the base terminal. By forming the interlock recess in the base terminal, it is no longer necessary to place the plug on the outer socket so that the fastener can catch laterally on the plug housing of the base terminal.
Advantageously, the electrical modular terminal is made such that the plug can be plugged not only selectively in one of the two sockets, but that, at the same time, one plug at a time can be plugged in the two sockets and that the two plugs can be mechanically connected to the plug housing of the base terminal. If the base terminal has two terminal elements to which two different potentials can be connected via electrical supply lines, because one plug at a time can be plugged into the two sockets, two potentials can be transmitted to the consumer side of the electrical modular terminal.
How the two plugs are formed, in particular, i.e., whether especially in the plugs there is one terminal element or several terminal elements, depends essentially on the available space, and thus, on the length of the base terminal. In applications in which there is no shortage of space, but in which there is the desire to be able to connect as many electrical lines as possible to the electrical modular terminal, there can be two or even more terminal elements in both plugs. However, generally, the available space is limited because the electrical modular terminal is to be accommodated, for example, in switching cabinets. Then, it is advantageous if the plug which is plugged in the outer socket has only one terminal element, while the plug which is plugged in the inner socket can have two terminal elements.
According to one preferred embodiment of the electrical modular terminal according to the invention, the detachment of the plug from the base terminal can be handled especially easily by making the fastener as an elastic catch arm with a handle section, a catch hook and a spring element, and by the catch arm being pivotally supported on the housing of the plug and the spring element being located above the bearing point. This configuration of the fastener yields two advantages independently of one another. Because the fastener is supported as an elastic spring arm with a pivoting capacity on the housing of the plug, and on its one end has a handle section and on its other end a catch hook, actuation of the catch arm is possible solely via the handle section which is easily accessible from the operator side. Thus, the plug can be easily detached by actuating the handle section with one finger. Use of a tool is not necessary. Because a spring element is additionally formed on the elastic catch arm, provisions are made for the catch arm to be permanently kept in its interlocked position when the handle section is not actuated.
According to another preferred embodiment of the electrical modular terminal in accordance with the invention, the fastener is connected to a strain relief element, and an electrical conductor which is connected to the plug can be attached to the strain relief element. In this configuration of the fastener, it thus assumes not only the function of mechanical locking or connection of the plug and the base terminal, but it is also used as strain relief for an electrical line connected to the plug.
In particular, there is a number of possibilities for embodying and developing the electrical modular terminal of the present invention, and especially the fastener as will be apparent from the following detailed description of preferred embodiments in conjunction with the accompanying drawings.